The present invention is concerned with providing a panoramic scanning system which is capable of scanning through a full 360.degree. revolution.
A primary utilization of such a scanning system is with a closed circuit television camera such as utilized for surveilance purposes within stores and banks today. The purpose of such a system is to enable a wider area to be viewed than generally possible with conventional systems generally utilized. In most conventional systems, in order to provide a scanning effect the entire camera must be rotated through the desired scanning angle. Typically the camera is placed against the wall with the camera rotating back and forth along the same path so that the scanning angle is less than 360.degree..
Several systems have been developed for enabling a panoramic view over a full 360.degree. revolution to be obtained. In developing these systems, there has been concern for avoiding the necessity of having to rotate the entire camera housing. Such systems are illustrated in the following U.S. Pats.: No. 2,905,758 issued to J. P. Walker; No. 3,610,825 issued to B. G. Fritzel; No. 3,634,622 issued to B. A. Wheeler; and No. 3,761,623 issued to A. Hara et al.
In the systems disclosed by all of these patents, a mirror member having a single reflective surface is arranged at an angle with respect to the optical axis of the camera. While the reflective surface of the mirror continuously faces the optical axis, the mirror is rotated through a full 360.degree. revolution. In this manner, a panoramic scanning view can be obtained. In order to maintain the image being viewed by the camera in the same orientation throughout the entire rotation of the mirror assembly, however, the camera head itself is simultaneously rotated in synchronism with the mirror. In order to rotate the camera itself along with the mirror, the drive motor must provide a relatively large torque due to the weight of the camera. Furthermore, it is generally considered to be desirable to try to maintain the camera in a stationary position if at all feasible.